Case 4: PHP parser outside of web tree

A very secure option is to put the PHP parser binary somewhere
outside of the web tree of files. In /usr/local/bin, for example. The only real
downside to this option is that you will now have to put a line
similar to:

#!/usr/local/bin/php

as the first line of any file containing PHP tags. You will also
need to make the file executable. That is, treat it exactly as
you would treat any other CGI script written in Perl or sh or any
other common scripting language which uses the
#! shell-escape mechanism for launching
itself.

To get PHP to handle PATH_INFO and
PATH_TRANSLATED information correctly with this
setup, the PHP parser should be compiled with the --enable-discard-path
configure option.